To the surprise of many oobservers, the Missouri Supreme Court decided that the limitless system as passed was unconstitutional. Since lawmakers had begun to take unlimited donations, it caused quite of bit of confusion throughout the Missouri political establishment.

Ultimately, lawmakers were forced to refund millions of dollars of "over limit" donations. This act was significant on paper, but many were able to either filter the money back through outside campaign committees. And many received much of the money back when limits were taken off again in 2008.

Still, the decision affected how the political class raised money for nearly an entire calendar year. And it provided a glimpse at the difficulties of curbing big money in politics.

WHY IT MADE THE LIST: I've always been fascinated with efforts to either curb or expand campaign finance limits. Republicans generally seem content with allowing huge donations if the act is "transparent." But Democrats and some Republicans often support a limited system that is easily circumventable and provides much more power to outside groups.

This challenge can be seen on a federal level. Groups like the Club for Growth or Emily's List can spend unlimited amount of money doing essentially the same thing a candidate's committee does on a daily basis. And if a federal legislative race gets competitive, you'll likely see the National Republican Campaign Committee or the Democratic Congressional Campaign Committee get involved.

The Trout case was the latest chapter in the difficult history of controlling campaign contributions.

FUN FACT: Trout unexpectedly won a state Senate primary for a St. Louis County Senate seat. He was soundly defeated by Eric Schmitt, an attorney who is now in the Missouri Senate.